Not sure how I would feel about it. I really liked the Beyonder used in the original Secret Wars more then the retconed version of him, which is only a fraction of his original power. However, it might be a good way to introduce him, since it does have some ties to the comic despite it not being his real origin story.
However, I think what I would rather see though (which also does not truly follow the comics) would be that we have Thanos as a villian in Guardians of the Galaxy and have him get a hold of the Infinity Gauntlet at the end of it leading into Avengers 2 where earths mightiest heroes along with the guardians of the galaxy square off against Thanos and the Infinity Gauntlet, and perhaps when all seems lost for all the heroes because they are getting their @$$e$ handed to them by Thanos, the cosmic cube calls upon the being known as the Beyonder from beyond (where he is not the cube itself, but just summoned by it), who stops Thanos restores the universe to it's rightful order, and then disappears contemplating this whole good vs. evil concept. Then if things were almost perfect in my opinion they could go back to the original character movies (Iron Man, Thor, Captain America & Hulk, along with Ant Man, Dr. Strange, Black Panther & Guardians of the Galaxy) with standard more but more personal villians, if possible maybe they could also regain the rights for the Fantastic Four movie (I know long shot), or perhaps even create a Defenders movie and during the end credits of all of these movies have a short cameo showing the Beyonder talking to the "One above All" (not shown, but just almost as one would speak to god) about not understanding why good and evil exist and which one is more powerful. I see the Beyonder despite his Infinite powers, as being like a innocent child where he wants to understand "why", just hopefully they can do it without it seeming annoying. Lol
Then lead into a trilogy for a Marvel Super Heroes Secret Wars Movie, with basically a huge ensemble list of heroes vs. villians like nothing we have ever seen before.
Unfortunately, the only problem is where to go from there. Lol
Surfer